Say it's 3PM- half way through the day and you are realizing how crappy you've eaten today-overindulged, poor choices, been inactive, overslept, hungover... well tomorrow is a brand new day.
No. Begin your active recovery as soon as you find yourself engaging in the self dialogue of defeatism. Have something nutritious to eat to ward off cravings instead of starving to purge over indulgence. Exercise to improve energy, boost esteem and motivation.
Begin now. Just as every day is a brand new day, every moment is a brand new moment. Don't write off the rest of your day any more than you would the rest of your life!